A typical visual/audio display system consists of slide projectors, audio cassette decks and a viewing screen or video wall. Images on slides are displayed on the screen or wall in succession by the slide projectors. The slide projectors can change the displayed image without any perceptible delay by a viewer. The cassettes played in the audio cassette decks provide any audio which may accompany the images being displayed. Thus, with this system, a viewer observes a continuous display of changing images and hears accompanying audio, without any distracting transitions between the display of images.
New design challenges with conventional visual/audio systems, such as the one described above, have resulted from the advent of photo CD technology. Basically, photo compact disc (CD) technology has enabled data representing one or more images and audio associated with each image to be stored on a photo CD. To display an image and hear the audio, a photo CD player and a display device are needed. More specifically, when a viewer wishes to see an image stored on a photo CD and hear any associated audio, the photo CD is inserted into a photo CD player. The viewer inputs his selection to the photo CD player which selects the desired image on the disc and reads the stored data. The data is transmitted to the viewing device to display the image and play any associated audio. The image remains on the screen until the viewer inputs his next selection, causing the photo CD player to select the next desired image and to read the stored data on the disc. The data is again transmitted to the viewing device, however before the viewing device can display the next desired image, a delay of approximately three to four seconds is needed to "wipe" the current image from the screen of the display device. To the viewer, "wiping" appears as the replacement of a first image by a second image. More specifically, the second image appears to replace the first image in discrete packets or lines. For example, the replacement appears to go line-by-line from top to bottom, column-by-column or diagonally in either direction. For many applications, this transitional delay is only a minor inconvenience, however with visual/audio systems which might use photo CD technology this delay is particularly problematic.
As noted previously, visual/audio display systems involve the presentation of a series of still images and audio. If photo CD technology was expanded into traditional visual/audio display systems, viewers would be subjected to a repeated delay between each image to be displayed, as the previous image is wiped from the screen or wall. This repeated delay during the change of images would be very distracting to viewers and as a result would detract from the overall visual/audio presentation.